Recent content by JohnD135

I understand about I squared R losses. Also the slope of the current increase with time in the inductance of the motor winding being effected by the motor back emf. Thanks for the tip about overheating at low speed. I will provide a heat path from the controller to the chassis. It doesn't...

You say your 22A is small and so can't lose heat. I suppose you are thinking that there is little room for air circulation and small surface area, etc. I take your point about higher speeds. If you have a limit on power, and power equals torque times revs and torque is proportional to current...

Thanks for your reply. Unfortunately I am committed to 36V, having two batteries at that voltage. I suppose, what I can do is to connect the controller to the frame to reduce the temperature of the case. The current location of the controller is about as bad as it could be from a thermal...

Forgot to say, my current controller is an S-KU65.

Hi All. I was biking across the North York Moors a few days ago and may have damaged the controller by pushing the bike up hills and using the throttle to assist. Since I am going to have to get into it, could one of you suggest something a bit tougher, or even sine wave? The current size is...

What I have started to do is to change the 7 speed cassette from 28-14T to 28-11T and the main cog from 52 to 42. If I have my sums right, this should give me the same ratio for road use (which I currently like) and improve my hill climbing by 1.25. Not quite right but close. Concerning...

Starting to change the gearing, etc, as suggested and discovered the motor details under the cassette. It is as follows "Permanent magnet brushless high speed hub motor used for electric bicycles ZL 2003 2 0123400.9" Does that suggest that I can increase the current by 30% or so, at my own...

Nealh, what is a freewheel please?

As to the mountain bike conversion, I can see the logic of a properly balanced bike for use on very challenging terrain with excellent hill climbing ability. I go off road now, but only byways and Forestry Commission tracks. Not really very challenging. I think I will refurbish (it needs front...

Wow! Thanks for all the advise guys. You have given me two avenues to investigate. Refurbish the Oxygen or convert the mountain bike. I have understood the, quite complicated, issues with gearing changes and can probably get more torque hill climbing ability by changing both the cassette and...

I suppose I am disappointed. I thought I would get significantly improved hill climbing performance with a mid drive. But thanks for all the advice everyone. I will try to increase the range of my existing cassette and also reduce the resistance of the current sensing loop in the controller...

The wheel size of the old and new bikes are the same. 42T to 28T is what I have giving, as you say, around 50nm from an 80nm motor. I am retired now, but from what I remember, most motors are limited at low revs by the dissipation in the windings. My battery has 7 cells in parallel (10 in...

I have an old Oxygen Ebike with a rear hub motor. The bike is nearly worn out. I bought it second hand before lock-down and have had lots of fun out of it. But so many things needing replacing that I have decided to convert a new mountain bike to electric. I will be using it off road so...

Thanks Nealh, it is a relief to know that this is possible, although, as you say, alignment may be an issue. As to the Oxygen bike that I have Saneagle, it is very old and I was thinking it might not stand the strain! As to the hills, I climb a few of them now but am now not so fit as I was so...

I am considering converting an MTB to electric. I already have an old Oxygen with a rear motor, but this is not so good on very steep hills. Otherwise it is brilliant! Is it possible to have two main cogs on a mid mounted motor please? So that I can manage very steep off-road?